Genetically obese hyperphagic rats were studied in an attempt to investigate the possibility that catecholamine levels in discrete areas of the brain may be altered. A significant decrease in the norephinephrine level was found in the paraventricular nucleus of the hypothalamus and an increase of this amine in the median eminence. No changes in norephinephrine or dopamine were observed in eight other hypothalamic areas. This is of interest in view of the fact that a prior study showed that injection of norepinephrine into the paraventricular nucleus elicits eating.